1. Field of the Invention
The present invention relates to a recording disc cartridge, and more particularly to a recording disc cartridge having shutters for opening and closing spindle holes and head insertion holes defined on the faces of the recording disc cartridge case.
2. Prior Art Discussion
Recording disc cartridges of the type having a recording disc of a magnetic or optical recording medium and a disc case made of a hard material with a generally flat rectangular shape are adapted to be mounted on a disc drive apparatus so that the recording disc is rotated and accessed by a magnetic recording head or an optical recording head for recording or reproducing the information. In order to access the recording disc by the head, the disc case is provided with head insertion holes and spindle holes for allowing the entering of a drive member of the disc drive on both faces of the disc case.
In order to prevent foreign substances or a finger from entering into the disc case, by which the recording disc may be stained, conventionally the disc case is provided with shutter members for closing and opening the respective head insertion holes. FIGS. 1 and 2 show one example of the recording disc cartridge of the above type, wherein reference numeral 1 denotes a disc case made of a top case half 2 and a bottom case half 3. A recording disc 4 is rotatably enclosed in the disc case 1, having a spindle hole 5 defined on the central portion of the disc case 1. A head insertion hole 6 is defined adjacent to the spindle insertion hole 5, with a shutter 7 for opening and closing the head insertion hole 6 having an opening 8 defined on the shutter. The shutter 7 is normally situated at the closed position for closing the head insertion hole 6 and when the recording disc is used the shutter 7 can be moved in a direction A by a shutter moving arrangement in a recording/reproducing apparatus, so that the head insertion hole 6 can be opened when the hole 8 comes in alignment with the head insertion hole 6.
In the conventional recording disc cartridge, the shutters provided on both planes of the disc case are adapted to be moved in one direction, therefore when the recording disc shown in FIG. 1 is reversed and mounted on a recording/reproducing apparatus, the shutter is moved in the direction B which is the reverse of the direction A for opening the head insertion hole 6. Accordingly, the recording/reproducing apparatus must be provided with two shutter opening mechanisms, one for moving the shutter in the direction A and another for the direction B to enable to use the dual type recording disc i.e., both faces of the recording disc are available for recording. Therefore the construction of the recording/reproducing apparatus is complicated.
Furthermore, if the conventional recording disc cartridge is not provided with a shutter arrangement for closing the spindle holes, foreign substances such as dust may enter the inside the disc cartridge. It is greatly required to provide an arrangement for preventing the introduction of dust inside the disc case in particular for optical recording discs having a large memory capacity.
Another problem of the conventional disc cartridge is that if the shutter for the head insertion hole is not completely opened when the disc cartridge is loaded on the recording/reproducing apparatus, the head in the recording/reproducing apparatus may erroneously strike on the shutter, thereby to damaging the head.